Dynamo-electric machine



Nov. 29, 1927.

1,650,947 M. LATOUR v DYNAMO ELECTRIC MACHINE Filed Sept. 29, 1924 Bag.1 PHASE 1 was 2 /i if 5 I PHASE 1 PHASE 2 PHASE 3 5 MAmUs LATOURINVENTOR ATTORNEY Patented Nov. 29, 1927.

UNITED STATES 1,650,947 PATENT OFFICE.

MARIUS LATOUR, PARIS, FRANCE, ASSIGNOR TO LATOUR GORIPOIRATIOII, OFJERSEY CITY, NEW JERSEY, A CORPORATION OF DELAWARE.

I DYNAMO ELEGTRIC MACHINE.

Application filed September 29, 1924, Serial No. 740,424, and in FranceApril 5, 1924.

The invention relates to multi-phase alternators of the high frequencytype adapted to wireless telegraphy.

These alternators are of the homopolar type and the invention ischaracterized by the relations established between the number of theslots on the stator and the number of the pole projections on the. rotorin these alternators. In my U. S. Letters Patent No. 1,234,914 there isdisclosed a method of providing relatively large spaces for the statorwindings in a homopolar high frequency alternator, by adopting a certaingeneral universal relation between the number of rotor teeth and thenumber of stator teeth. The disclosure in that patent referred to asingle phase alternator, that is, an alternator in which the currentsinhalf of the stator slots are all of the same phase, and the currentsin the other half of the slots being, re

turn currents, are in efiect of opposite phase.

The purpse of the present invention is to apply methods analogous tothose of the above-mentioned patent, but to polyphase alternatorsinstead of to single-phase alternators. The same advantage of providingrelatively large spaces for the stator windings is attained. This resultis even more slots and in the reverse direction in the other half. Thefactor (2n+ 1) represents essentially an number prime to 2, that isanyodd num e 7 Now the rule which is applicable to polyphase machines is ofthe same general form as that for single-phase machines; that the numberofstator'teeth should be pm and the number of rotor teeth gm, Where m isany positive integer, p is the number of stator phases, and g is'any oddinteger prime to p,

preferably 9 should be greater than go, but

not very much greater.

Take the case of What is ordinarily called a. two-phase, but which is,more exactly speaking, a four-phase alternator (because the currentdelivered by such alternator corresponds to four currents -22 or 90apart,

just as three phase current corresponds to three currents g or 120apart) comprising 4m stator slots, where m is any desired whole numberor integer. In conformity with the present invention, the number of poleproections or teeth in the rotor is made equal to (2n +l)m, n being anydesired whole number, for the expression (2n+'1) represents any numberprime to 4, as stated for g in the preceding paragraph. There shall moreparticularly be considered the case of n=2 whence there results a ratioof 4:5 between the number of stator slots and the number of poleprojections in the rotor.

Fig. 1 illustrates the invention as-applied to a two-phase machine; Fig.2, as" applied to a three-phase alternator. Fig. 1 illustrates the ideaunderlying this invention in connection with a homopolar machine therotor of which is denoted by'R, anl the stator by S. The coils of twodistinct phases are'expressly indicated in Fig. 1. The sectional shapeof the stator and rotor teeth is given for the sake of example.

Take further the case of a three-phase.

alternator comprising 3m stator slots, where m again Is any desiredinteger. In co'nformity with the invention the number of poleprojections in the rotor is chosen at gm, 9 being any desired odd wholenumber prime to 3, and there shall more particularly be taken the caseof 9:5 which results in a ratio of 3:5 between the number of statorslots and the number of rotor teeth.

Fig. 2 shows this latter embodiment of the invention. The coils of thethree phases are indicated especially in this figure, but the shape ofthe stator teeth and the rotor teeth 6 is again merely shown by way ofexample.

The case could .further be considered in which six-phase currents aredealt with, it being noted that for 6m slots in the rotor there areprovided gm projections or teeth on the rotor, 9 being prime to 6.

The advantage offered by three-phase currents, as'is well known residesin that they lend themselves particu arly for the tripling of thefrequency, while allowing of a notable saving in condensers andauxiliary coils.

With an even number of phases as in Fig. land with the tooth widthapproximately equal to the slot width on the rotor, the tooth width onthe stator may advantageously be made approximatel equal to the toothwidth on the rotor, as iliustrated. Onthe other hand, with an odd numberof phases, as in Fig. 2, the stator tooth width will need to di er fromthe rotor width in order to maintain constant reluctance between therotor and the stator as required in a homopolar machine.

While I have shown and described various referred embodiments of myinvention I 0 not limit myself to the same, but may em 10y such othermodifications as come wit the spirit/and scope of my invention.

Claims:

1. A homopolar polyphase high-frequency generator of p phases having pmteeth on th stator, a winding on each of said teeth, and

teeth or polar projections on the rotor, where m is an integer and g isan odd integer greater than p an prime to p. 2. A. homopolar polyphasehigh-frequency generator of 4 phases having 4m teeth on the stator, awinding on each of said teeth, and (2n+1)m teeth or polar projections onthe rotor, where m is an-integer and n is an integer greater than 1.

3. A homopolar polyphase high-frequency generator of 4 phases, havingelm teeth on the stator, a winding on each of said teeth, and 5m teethor polar projections on the rotor.

4. A homopolar polyphase high-frequency generator of an even number ofphases p h ving pm teeth on thestator, a winding on each of saidteeth,and gm teeth or polar projections on the rotor, where m is an integerand g is an integer greater than 7) and prime to p, the tooth width andslot width on the rotor bein approximately equal and the tooth widx onthe stator being approxi mately equal to the tooth width on the rotor.

. mmsj m'roun.

